This invention relates to a cordless telephone arrangement comprising a base station coupled to a telephone network, and a plurality of mobile stations capable of communicating selectively with other telephones on the network via a radio link with the base station.
At the present time a variety of cordless telephone systems exist within Europe. For example some countries such as France and UK have adopted national specifications using low frequencies under 50 Mhz. An analogue system known as CT1 has been adopted by other countries. A digital system based on frequency division multiple access (FDMA) known as CT2, has been developed in the UK. In Sweden the CT3 system has been developed which is a time division multiple access (TDMA) digital system.
Additionally, the European Telecommunications Standards Institute (ETSI) has proposed a standard cordless system known as Digital European Cordless Telephone (DECT), which offers a quality of communications comparable with standard land-line telephones. The DECT concept is one of versatility of applications at a cost intended to encourage wide availability and market adoption. The DECT concept includes a definition of personal portable communications based on small, easy to use terminals. Thus DECT is intended to offer low-power cordless access between a portable terminal and the DECT infrastructure at ranges of up to several hundred metres from the base station.
Apart from the residential application which would interconnect DECT to a PSTN with the features and responses of a standard fixed-wire telephone, a DECT Business Cordless Telecommunications system (BCT) is envisaged that combines the features of a private branch exchange (PBX) with the mobility of cordless telecommunications for both voice and non-voice applications.
A common feature of the known cordless systems mentioned above is that in each case the mobile station, ie the telephone itself, conventionally comprises a user-interface including a display and a keypad having a plurality of buttons or keys which can be depressed by the user in order to operate the telephone, ie to dial a telephone number or perform other functions such as for example to display a telephone number or other data stored in memory. Generally, the keypad comprises two main sets of keys, namely a first set of alphanumeric keys associated with alphanumeric data, including the digits 0-9 inclusive, particularly for dialing telephone numbers, but also (optionally) for entering alphanumeric data into the telephone memories, eg a subscriber number index; and a second set of function keys for enabling previous predetermined functions or operations. Included in the second set of function keys, for example, may be a special key for initiating and terminating a telephone call. Another of the function keys may be a menu key, actuation of which enables a variety of pre-set menus to be viewed and selectively enabled. A particular menu option may be selected using another key on the keypad.
Both displays and keypads have certainly gained universal acceptance in the cordless telephone industry and indeed there is a high level of commonality of the keypad for telephone applications generally. However, the size and volume of the keypad mechanism and associated electronics necessarily contribute to the overall size and weight of the telephone handset.
Also, the requirement for a keypad and, possibly a display, imposes significant ergonomic and aesthetic constraint on the overall design of a cordless telephone handset.
In the context of mobile telephones for use inside vehicles, where safety considerations are important, but the weight and volume of the overall apparatus are less critical than for portable telephones, it is known to provide a voice recognition facility whereby numbers may be dialed in response to commands uttered by the user without the need for manual dialing. This function is commonly known as voice-activated dialing. It is noted that in known arrangements the voice recognition facility is provided within the terminal apparatus and the dialing operation is performed locally by the mobile telephone apparatus itself. Conventionally, the voice-activated dialing function is provided as an adjunct to the manual dialing facility and hence the telephone is generally also provided with a standard keypad. A mobile telephone with voice-activated dialing is disclosed, for example, in U.S. Pat. No. 5,042,063.
According to the present invention there is provided a cordless telephone arrangement comprising a base station coupled to a telephone network, and a plurality of mobile stations capable of communicating with other telephones on the telephone network via a radio link with said base station, wherein the base station is adapted to dial a telephone number automatically for a mobile station in response to an instruction received by radio communication from the respective mobile station whereby the mobile station may selectively address other telephones on the network.
In accordance with the invention dialing is performed remotely by the base station on behalf of the individual mobile stations in response to an instruction sent by radio communication from the mobile station to the base station. The instruction may be given orally to the mobile station, that is to say the user may simply speak the telephone number to be dialed. Alternatively, the user may be presented with a predetermined list of telephone numbers, eg shown on a display on the mobile station, from which the number to be called may be selected eg with the aid of a movable cursor.
A cordless telephone arrangement in accordance with the present invention thus has the advantage that a telephone number is dialed remotely without the need to enter the number onto a keyboard at the mobile station. Indeed in a preferred embodiment the mobile station may comprise no independent means for dialing a telephone number. Specifically the mobile station need not include a keyboard. This enables the mobile station to be more compact and lightweight and permits much greater freedom in designing the mobile station.
In the case where the telephone number is dialed by voice command from the mobile station there is also no need for the mobile station to include a visual display, thereby further enlarging the scope for design freedom.
In a particular embodiment the mobile station further comprises means including, for example a button actuable by the user, for initiating a signal to be transmitted to the base station indicating a request to open communication. Thus the user is required merely to press a single button to signal to the base station that the dialing facility is required.
Suitably the base station may return a message by radio communication to the mobile station which has requested communication acknowledging receipt of the request, and inviting the user to select a service from a predetermined set of available services. The predetermined set of services may include, for example, remote dialing, re-directing an incoming call, storing or retrieving a number in or from a memory etc.
In one embodiment the base station includes voice synthesizing means for conveying a spoken message to the mobile station. Alternatively the different services available may be indicated on visual display means on the mobile station, and a particular service may be selected e.g. with the aid of a movable cursor.
Preferably the base station is adapted additionally to provide automatically for a mobile station a service other than dialing a telephone number in response to an instruction received by radio communication from the respective mobile station. The services provided remotely at the base station may for example include call re-direction, and/or storing or retrieving a number in or from a central memory in the base station.
Specifically the mobile station may take the form of a portable handset and the base station may take the form of a private branch exchange (PBX), for example in the context of a DECT BCT.